GrammarBrain Community
Log inRegister
Sentence StructureHas accepted answer

Can someone explain how to use relative clauses? I'm not sure about 'who' vs 'which'

Asked byJin ParkPosted Mar 21, 2026 2:18 PM3 answers27 upvotesCanonical URL

I'm writing a letter to my English-speaking friend, and I want to describe my teacher. Should I say 'My teacher, who is very kind, helps me a lot' or 'My teacher, which is very kind, helps me a lot'?

I'm confused about when to use 'who' and 'which' in these situations. Also, do I always need commas before and after the clause? I'd appreciate some examples to help me understand how relative clauses work!

Context:
I'm preparing for the B2 Cambridge exam and want to make my sentences more complex.

#relative-clauses

What to Know

Question You Likely Still HaveDirect AnswerHow To Apply It
What is the core rule for someone explain relative clauses?Pattern: [Person] + who + [extra info] [Thing/animal] + which + [extra info] Examples: My neighbor, who is very friendly, always says hello.Example correction: My friend, which always helps me → My friend, who always helps me .
How do I apply someone explain relative clauses in a sentence like mine?Relative clauses give extra information about a noun, and the word you choose depends on the noun type.Practice suggestion: Write two sentences: one about a person you know, and one about your favorite object, using 'who' and 'which'.
What mistakes should I avoid with someone explain relative clauses?Example correction: My friend, which always helps me → My friend, who always helps me .Use 'who' for people, and 'which' for things or animals (not people).

3 Answers

ByNora GrammarMar 21, 2026 2:38 PM9 upvotesAccepted answer

Relative clauses give extra information about a noun, and the word you choose depends on the noun type. Use 'who' for people, and 'which' for things or animals (not people).

Pattern:

  • [Person] + who + [extra info]
  • [Thing/animal] + which + [extra info]

Examples:

  • My neighbor, who is very friendly, always says hello. (person)
  • The book, which I finished yesterday, was excellent. (thing)

As for commas: use them to separate non-essential (extra) information. If the clause just gives extra detail, use commas. If it defines which person/thing you mean, don’t use commas.

Practice suggestion: Write two sentences: one about a person you know, and one about your favorite object, using 'who' and 'which'. Then check: did you use 'who' for a person? 'Which' for a thing?

Self-edit tip: If you write about a person and use 'which', quickly swap it for 'who'. Example correction: My friend, which always helps me → My friend, who always helps me.

ByPunctuation PaulMar 21, 2026 2:58 PM9 upvotes

Let's see how 'who' and 'which' operate by comparing similar sentences:

  • The teacher who explains clearly is popular. (Correct: 'who' because 'teacher' is a person.)
  • The classroom which has big windows is bright. (Correct: 'which' because 'classroom' is a thing.)

Notice:

  • Use 'who' for people (teacher, friend, mother).
  • Use 'which' for objects or animals (class, book, dog).

Commas: Use commas when the information is extra (not necessary to know who/what you mean).

  • My teacher, who comes from Spain, is helpful. (Extra information – use commas)
  • The student who arrives first gets the front seat. (Identifies which student – no commas)

Practice: Try pairing nouns with 'who' or 'which', e.g., 'My friend ___ likes music' and 'The chair ___ is broken', and fill in the blank with the correct word.

Correction practice: If you ever write 'a teacher which', change 'which' to 'who' – think: is it a person?

ByRavi AdminMar 21, 2026 3:18 PM9 upvotes

Think of 'who' as a connector for people and 'which' for things or animals. Ask yourself: Is the noun a person? Use 'who.' Is it a thing? Use 'which.'

Examples:

  • My cousin, who lives in Canada, speaks three languages. ('who' = person)
  • The film, which won an award, was directed by a famous actor. ('which' = thing)

Commas: If the clause is extra information, use commas. If it identifies the person or thing, no commas:

  • The man who fixed my car did a great job. (Identifies – no commas)
  • My car, which is ten years old, still works well. (Extra detail – with commas)

Guided practice: Write one sentence about a person and one about an object in your room. Then switch 'who' to 'which' (or vice versa) and notice if the meaning changes or becomes incorrect.

Correction: When you reread your sentences, underline the noun before the relative clause and decide: person = who, thing = which.

Want to answer this question? Log in or create an account.